Many of today's manufacturing procedures involve a conveyor of one sort or another, and in some systems a slide rail consisting of joined rail sections is used for moving work pieces along a manufacturing line. For example, articles may be placed on, or suspended from, carriages that travel along a rail from one work station to another. The carriages may travel continuously or may move and be stopped intermittently. For example, the carriage may be transported along a series of modular work stations, where a different operation is performed on the work piece at each station.
When precision in carriage location on the rail is important, such as in the automated production of relatively small electronic devices, the carriage typically is designed to be held in fairly close contact with the rail. For example, in some slide rail systems the rail has a specific profile allowing it to be embraced by part of the carriage during operation, such that the carriage generally cannot be lifted upward (or titled to the side) while mounted on the rail. This may be helpful in assuring that the carriage can be placed in an exact position for robotic operations on the work piece, to name just one example.
The close fit between carriage and rail may, however, also be associated with disadvantages. It becomes increasingly important that adjacent different rail sections are well aligned. If the misalignment is severe enough, it may be practically impossible to join the two rails in their current position. However, even when two misaligned rails can be joined to each other, the misalignment may cause a kink at the joint which can obstruct carriage travel. These difficulties can be troublesome in a manufacturing process involving modular work stations, when it can be difficult to precisely align adjacent work stations so that their respective rail portions can be joined. Such difficulties may arise also in non-conveyor applications, such as a component that travels over joined sections before reversing direction to return over the same sections.
It is to these and other problems that the invention is directed. For example, embodiments of the invention may offer the advantage of overcoming angular, lateral or twisting misalignments.